Internal combustion engine with sound-proof v-belt pulley

ABSTRACT

An internal combustion engine comprising a divisible sound-proof sheathing arranged in front of the crank wheel cover and attached thereto elastically and in a sound-proof manner, and enclosing the vee-belt pulley attached to the crankshaft, said sheathing presenting at each of the passages of the vee-belt an absorptiontype silencer closely encompassing the vee-belt.

United States Patent 1191 Thien et al. Feb. 4, 1975 INTERNAL COMBUSTION ENGINE WITII 3,530,840 9/1970 Freyn 123/41-7 SOUND PROOF V BELT PULLEY 3,540,425 11/1970 Scheiterlein 181/33 K 3,601,101 8/1971 Thien 123/4l.7 Inventors: Gerhard Thien; Heinz Fachbach, 3,684,053 8/1972 Fachbach.. 123/198 E both of Graz, Austria 3,693,602 9/1972 Thien I 123/195 C 3,695,386 10/1972 Th'en..... 181/33 K [73] AS81811! Hans Ausma 3,762,497 10/1973 Hall 181/33 K 22 FiledZ 8, 1973 3,796,280 3/1974 Thien 123/198 E PP N03 414,098 Primary ExaminerManuel A. Antonakas I Assistant Examiner-Daniel J. OConnor 7 [30] Foreign Application p Data Attorney, Agent, orFirm-Watson, Cole, Grmdle &

3 Nov. 10, 1972 Austria 9617/72 Watson 52 us. (:1. ..123/195 C,123/198 E, 181/33 K [57,] ABSTR ACT 51] Int. (31- 'E04b 1/99, GlOk 11/04 An internal combustion 903109 9911119118109 9 dwlslble [58] Field of Search 181/33 K; 123/195 c, 41.7, sound-proof sheathing arranged in from of the crank 123/198 E, 41,65 wheel cover and attached .thereto elastically and in a I sound-proof manner, and enclosing the vee-belt pulley 5 References Cited attached to the crankshaft, said sheathing presenting UNTED STATES PATENTS at each of the passages of the vee-belt an absorption- 2,730,0s7 1/1956 Morton 123/198 E type s'kmcer Closely encompassmg T 3,464,398 9/1969 Scheiterlein 181/33 K 2 Claims, 2 Drawing Figures PATENTEDFEB 4% 3,863,617

' sum 2 or 2 FIG? INTERNAL COMBUSTION ENGINE WITH SOUND-PROOF V-BELT PULLEY The invention relates to an internal combustion engine comprising a vee-belt pulley in a sound-proof sheathing arranged in front of the crank wheel cover.

In internal combustion engines of conventional design the vee-belt pulley located at the crank wheel end of the crankshaft and serving for the operation of the fan, the dynamo and other auxiliary machines, frequently is one of the major sources of noise. This loud noise is produced by direct intromission of sound through the rigid connection from. the crankshaft and is also ascribable to the resonance potential of the pulley proper. Minor improvements can be achieved by increasing the self-damping properties of the pulley and by displacing its natural oscillation frequency from the frequency range predetermined by the engine.

Another solution of high acoustic efficiency consists in the two-piece design of the vee-belt pulley wherein the pulley body proper is connected to the hub by means of intermediate-vulcanized rubber material in such a manner as to provide sound-proof insulation. However, the satisfactory acoustic effect of this design is offset by considerable shortcomings such as high manufacturing costs of the vulcanization process and the low fatigue strength of the elastic intermediate layer due to alternating stress. For considerations of better acoustics the elastic intermediate layer should be located as close to the crankshaft as possible and is therefore, subject to considerable shearing stress.

Highly effective screening of the pulley noise can be expected from a sound-proof sheathing of the vee-belt pulley, although the sound-proof passage of the veebelt(s) involves considerable difficulties. In such solutions as have been devised so far for the sound-proof sheathing of vee-belt pulleys, the sealing of the. passages was either omitted altogether or was attempted by means of brush-type elements the acoustic efficiency of which was almost nil. The relative inadequacy of these known measures has so far been the major stumbling block in their way to success.

It is the purpose of the present invention to provide an internal combustion engine of the type hereabove specified with a highly efficient soundproofing sheathing of the vee-belt pulley by simple means avoiding the drawbacks of known solutions. According to the invention, the sound-absorbing sheathing of the vee-belt pulley comprises a sheathing member elastically attached to the crank wheel cover in a sound-proof manner and partly embracing same and a cover removably attached to the sheathing member and located in front of the vee-belt pulley, both the sheathing member and the cover presenting sound-absorbing inserts at the passages of the vee-belt(s), said inserts combining to form an absorption-type silencer closely encompassing the vee-belts.

By means of this arrangement the sound-projection from the belt apertures of the sheathing of the vee-belt pulley is reduced to the minimum so that the acoustic effect of the sheathing is in no way impaired by the presence of belt apertures. In addition to the acoustic advantages of the measures according to the invention, the low production costs, long service life and convenient accessibility of the vee-belt(s) deserve also mentioning.

Further details of the invention will become apparent from the following description of an embodiment of the invention with reference to the accompanying drawing in which FIG. 1 shows a partially vertical cross-sectional view of an internal combustion engine according to the invention, and

FIG. 2 shows a front-end view of the internal combustion engine according to FIG. 1.

To the crank wheel end of the crankshaft l of the engine shown a sleeve-like intermediate piece 3 is attached by means of bolts 2 and extends through the crank wheel cover 4 of the engine and comprises a fixing flange 5 to which the vee-belt pulley 6 for the drive of the cooling air blower 7 and the generator 8 is attached by means of bolts 9.

The vee-belt pulley 6 is located inside a sound-proof sheathing 10 consisting of a sheathing member 11 elastically and sound-proofingly adjoining the crank wheel cover 4 and a cover 12 attached thereto by means of rapid-locking devices 13 in such a manner as to be readily removable.

At the passages 14 of the vee-belt 15 through the sound-proof sheathing 10 both the sheathing member 11 and the cover 12 are provided with sound-absorbing inserts 16, each of which is combined with the other to form an absorption-type silencer closely encompassing the vee-belt 15. Therefore, only a narrow gap is left at the passages 14 between the vee-belt 15 and the soundabsorbing inserts 16, as a result of which the projection of sound at these passages is considerably reduced.

I claim:

1. An internal combustion engine having a crankshaft, a crank wheel and further comprising a vee-belt pulley arranged in front of the crank wheel cover and non-rotatably connected with the crankshaft, a soundproofing sheathing encompassing said vee-belt pulley and consisting of a sheathing member elastically attached to said crank wheel cover so as to provide sound-proof sealing and partly embracing said vee-belt pulley, and a cover located in front of the vee-belt pulley and removably attached to said sheathing member, vee-belts extending through said sound-proof sheathing at two passages, sound-absorbing inserts being provided on said sheathing member and said cover at the passages of the vee-belt, said sound-absorbing inserts combining at each passage to provide an absorptiontype silencer closely encompassing the vee-belt.

2. An internal combustion engine according to claim 1, wherein at each passage at least two vee-belts driven by means of said vee-belt pulley extend through the sheathing. 

1. An internal combustion engine having a crankshaft, a crank wheel and further comprising a vee-belt pulley arranged in front of the crank wheel cover and non-rotatably connected with the crankshaft, a sound-proofing sheathing encompassing said vee-belt pulley and consisting of a sheathing member elastically attached to said crank wheel cover so as to provide sound-proof sealing and partly embracing said vee-belt pulley, and a cover located in front of the vee-belt pulley and removably attached to said sheathing member, vee-belts extending through said sound-proof sheathing at two passages, sound-absorbing inserts being provided on said sheathing member and said cover at the passages of the vee-belt, said sound-absorbing inserts combining at each passage to provide an absorption-type silencer closely encompassing the vee-belt.
 2. An internal combustion engine according to claim 1, wherein at each passage at least two vee-belts driven by means of said vee-belt pulley extend through the sheathing. 